XII 



XENOSAURIDAE ZONURIDAE ANGUIDAE 



537 



guidae by its snake-shaped body, extremely loug tail, and 

 vestigial limbs. In Ch. aenea both pairs of limbs are still 

 present and pentadactyle, but are very small ; in Ch. anguina the 

 limbs are reduced to little styliform stumps ; and in Ch. macro- 

 is they are altogether absent. The scales of the body and 



iL-eCii 



Fig. 135. — Zommis giganteus. 



tail are strongly keeled and imbricating, but are devoid of dermal 

 ossifications. Total length up to 2 feet. 



Fam. 5. Anguidae. — Pleurodont lizards with osteoderms, and 

 with the tongue composed of two distinct portions, of which the 

 anterior is thin, emarginate, extensible, and retractile into the 

 posterior thicker portion. The supratemporal fossa is roofed in 

 by dermal bones. The whole body is protected by bony plates 

 underlying the imbricating scales. The teeth vary much in 

 shape, but they are always solid, the new teeth not growing into 

 the base of the old ones, but between them. The limbs are in a 

 very unstable condition, there being in the family a general 

 tendency to reduce and lose the limbs. The shoulder- and 

 pelvic - girdle however remain, although sometimes merely 

 vestigial. The tail is long, very brittle, and easily reproduced. 

 All the Anguidae are strictly terrestrial, and live on animal diet. 



